Those who have always hated the idea of the current Speaker [Michael Martin] occupying the chair of this house have abused this situation to seek further to undermine him.

What I say to the House of Commons is this: the Tory party has created a bogus controversy about the abuse of privileges that do not exist and the need for a warrant that is not required. We are wasting this afternoon when it could have been used for this house to debate serious and relevant issues about which our constituents care deeply. They do not care in the slightest.

These interruptions show what the Tories believe about whistleblowing and free speech. They do not care about free speech. They want to divert the electorate's attention from the real issues to this bogus issue of what the honourable member for Ashford [Green] did or did not do, about which, frankly, our constituents do not give a damn.

In this matter, the leader of the house [Harriet Harman] has special responsibilities. She is a government minister, but she also has responsibilities to the house, so I ask her to reflect on something. It is generally accepted that John Biffen and Robin Cook, both, sadly, no longer with us, were the epitome – the best examples – of leader of the house in recent times. What would John Biffen and Robin Cook have done in similar circumstances? I believe that they would have asserted the independence of this House of Commons.

When I criticised something that a colleague – he is no longer in his place – had said earlier, he said: "Well, what about paedophilia?" I said that if an honourable member were guilty of a serious crime, such as pushing drugs or being a member of the mafia, the Speaker could take cognisance of a legitimate representation made to him by law enforcement officers and would say: "Yes, of course you must proceed forthwith." The role of the Speaker is to be a safeguard, and that is what we must ensure. Let us kill the lie now: no one is asking for special privileges for members of parliament. We want any bad member to be prosecuted with vigour, but we need to safeguard people from arbitrary action by the executive arm of government.

Frankly, I find that use of the offence of misconduct in public office very worrying. I received an email today – perfectly legally – from a recently retired senior police officer, who said the following about misconduct in public office: "This is a catch-all or fallback, flavour of the month, supposed offence that the Met[ropolitan police], Thames Valley and at least one other police force" often pursue. He continued: "They have used it to contrive allegations of criminal conduct against a large number of public servants. Overwhelmingly, those investigated have faced years of debilitating investigation that has damaged their lives as well as their careers and the lives of their families but have faced no criminal charges of any kind or, even, disciplinary charges related to the supposed misconduct investigated. In the vary rare convictions for the supposed serious criminal offence, the sentences have been the lightest tap on the wrist and all costs have had to be met by the crown."

He goes on to assert that more than 50 civil servants have faced that process.

I am worried about the Met, given their behaviour in the so-called "cash for honours" case, and the case of the right honourable member for Neath [Peter Hain]. When the police are called in they should not think: "Here's a good public interest case. We'll get a lot of good publicity out of this; it'll be a good, high-profile thing." They should have said to the Cabinet Office: "This is not a matter for us. Go away and sort it out inside the department itself."

Today's news that the Commons home affairs will launch its own inquiry into the Damian Green affair will be doubtless be welcomed by those who have been complaining about the government's attempt to postpone an investigation. But anyone hoping for conclusions that embarrass Jacqui Smith or anyone else in government is in for a disappointment?